Another new battery prototype

Angilion · 27 Jan 2014 at 23:36

This one generates electricity from sugar and stores it, so in a sense it's a generator as well as a battery.

http://www.nature.com/ncomms/2014/140121/ncomms4026/full/ncomms4026.html

A refillable battery sounds like 50+ years ago, but it could be very useful for an EV because you could refuel it rather than recharging it or swapping the battery for a recharged one. Since the fuel for this one is a mixture of sugar and water, storage of it would be quite simple and could be added to petrol stations quite easily, so it would be practical to do it to whatever scale is suitable to the number of EVs in use. You could safely make the fuel at home too - bag of sugar and a bucket of water.

But if I'm right then the battery doesn't have a high enough power output to be practical for powering an EV. Plenty of storage capacity, but not enough grunt. Am I right about that?

Of course, it's just a prototype in a lab at the moment. Plenty of things reach that stage but never become practical. Still, it's an interesting possibility. The biggest problem with EVs is getting electricity to the motor, so if that was sorted out with new batteries then EVs might become viable.

miniyazz · 28 Jan 2014 at 02:53

I noticed that, I heard somewhere it might become viable technology for portable devices within about 5 years or so but of course everything like this is really vapourware until it actually arrives.

Energy density they reckon "an order of magnitude higher than Li-ion" and quote 596Ah/kg. Unfortunately they don't give a voltage figure and the Ah figure is rather useless by itself. If that's with a voltage of 1V then we are looking at something around 5x higher than Li-ion; I'm not convinced by the argument of too low a power output for EV because surely it's possible to connect smaller cells in serial if required? It's not like they've got severe weight restrictions, Li-ion systems in cars are currently several hundred kilos I believe

Angilion · 28 Jan 2014 at 03:53

miniyazz said:
I noticed that, I heard somewhere it might become viable technology for portable devices within about 5 years or so but of course everything like this is really vapourware until it actually arrives.

Energy density they reckon "an order of magnitude higher than Li-ion" and quote 596Ah/kg. Unfortunately they don't give a voltage figure and the Ah figure is rather useless by itself. If that's with a voltage of 1V then we are looking at something around 5x higher than Li-ion; I'm not convinced by the argument of too low a power output for EV because surely it's possible to connect smaller cells in serial if required? It's not like they've got severe weight restrictions, Li-ion systems in cars are currently several hundred kilos I believe

They do have severe size restrictions, though, and there are limits to how many cells you can feasibly connect in series. It's no use if you need a car-sized battery to power a car

They give figures for wattage and current per size and the wattage is far lower than Li-ion, about 12% of some prototype Li-ion batteries (0.8 W/cm^2 compared with 7.4 W/cm^2). That implies a rather low voltage and current. That would explain why they're talking about this as a potential battery for small mobile devices and not anything power-hungry. Although I suppose it's not strictly speaking a battery - it's a fuel cell.

miniyazz · 28 Jan 2014 at 12:45

Angilion said:
They do have severe size restrictions, though, and there are limits to how many cells you can feasibly connect in series. It's no use if you need a car-sized battery to power a car They give figures for wattage and current per size and the wattage is far lower than Li-ion, about 12% of some prototype Li-ion batteries (0.8 W/cm^2 compared with 7.4 W/cm^2). That implies a rather low voltage and current. That would explain why they're talking about this as a potential battery for small mobile devices and not anything power-hungry. Although I suppose it's not strictly speaking a battery - it's a fuel cell.

Being as the batteries are obviously radically different design, I'm not sure how well measuring power in cm² can be compared - surely cm³ would be a much better method? Even though that would probably be subject to more variability with different designs.

Anyway it'll be interesting to get some more figures on power output and size required